Does using images instead of text affect email deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 15 Jun 2025
Updated 19 Aug 2025
6 min read
A common concern in email marketing is whether substituting text with images can negatively impact email deliverability. This often stems from older advice about spam filters and image-to-text ratios. It is understandable why this question continues to surface, especially with the prevalence of visually rich email campaigns.
While email images have the power to amplify messaging and drive engagement, they have also been known to cause deliverability issues and negatively impact a recipient’s experience if not used correctly. The key here is to understand the nuances of how modern email systems evaluate content.
The short answer is yes, using images instead of text can affect deliverability, but not always in the way you might think. It is less about a direct penalty for image quantity and more about the broader implications for accessibility, user experience, and how sophisticated spam filters interpret your email's content and intent. It is important to approach email design with a balanced perspective.
The persistent myth of image-only emails and spam filters
The idea that image-heavy emails without much text can raise a red flag for spam filters is a long-standing theory. This notion originated because spammers sometimes used (and still do, in less sophisticated attacks) image-only emails to bypass early keyword-based spam filters. By embedding their illicit messages within an image, they hoped to evade detection, as the text within the image was not directly readable by the filters.
However, email filtering has evolved significantly. Modern spam filters are far more sophisticated than they once were, relying heavily on sending reputation, authentication (like SPF, DKIM, and DMARC), engagement metrics, and complex content analysis. While an extremely high image-to-text ratio, especially if the email consists solely of images, might still be a minor signal, it is rarely the primary factor in an email being flagged as spam. The idea is that image heavy emails without much text can raise a red flag for SPAM filters.
In fact, research has shown that for emails with 500 characters or more, the content-to-image ratio has minimal impact on deliverability. Spam filtering is now based much more on sending reputation than content, though image to text ratio does still carry some weight with spam filters. Focus on building a strong sender reputation and ensuring proper email authentication. We have a detailed guide on whether image-to-text ratio is still important for deliverability.
Beyond deliverability: accessibility and user experience
Even if the direct deliverability impact is less than once thought, using images instead of live text introduces significant challenges for accessibility and user experience. Many email clients, especially on corporate networks, block images by default. If your entire message relies on an image, recipients might see a blank space or a broken image icon, completely missing your content. This is a critical reason why you should never send image-only emails.
Accessibility is another major concern. Screen readers for visually impaired users cannot interpret text embedded in images without proper alt text. This excludes a significant portion of your audience and can be seen as a negative signal by inbox providers. The experience could also be negatively impacted if images are not displayed.
Furthermore, large or unoptimized images lead to slow loading times, which frustrates users and can cause your email to be truncated (clipped) by services like Gmail. This hides important content, including unsubscribe links, and negatively impacts user engagement, which, in turn, can affect your deliverability over time. Poor engagement signals a lack of interest to inbox providers, potentially leading to future filtering issues.
Best practices for image use in emails
Instead of replacing text with images, focus on using images to enhance your message. Here are some best practices:
Alt text is vital: Always provide descriptive alt text for all images. This ensures your message is conveyed even if images are blocked or for users relying on screen readers. It also provides valuable context to spam filters.
Balance images and live text: A simple design can help reduce the likelihood that an email will be flagged as spam. Ensure your emails contain a healthy amount of live, crawlable text, especially for critical information and calls to action. A common recommendation is to aim for at least 60-70% live text.
Optimize image file sizes: Compress images to reduce file size without sacrificing quality. This improves loading times and prevents email clipping. Consider if self-hosting images affects deliverability.
Responsive design: Design your emails to be responsive, ensuring images scale correctly and display well on all devices, from desktops to mobile phones.
Always include a plain text version of your email to ensure content is accessible to all recipients and email clients.
Use clear, descriptive alt text for every image. This is crucial for accessibility and when images are blocked by default.
Keep images optimized for web, compressing them to reduce file size and improve loading speed.
Maintain a healthy text-to-image ratio, ensuring your core message is conveyed through live text, not just visuals.
Test your emails across various email clients and devices to ensure images display correctly and do not break layouts.
Common pitfalls
Sending image-only emails: This is a red flag for spam filters and offers a poor user experience for recipients with images disabled.
Neglecting alt text: Without alt text, your images are invisible to screen readers and provide no context when not displayed.
Using unoptimized, large images: This leads to slow loading times, potential email clipping, and a frustrating user experience.
Relying on images for critical information: If images fail to load, crucial calls to action or key messages may be lost.
Failing to test responsive image behavior: Images that do not scale correctly can ruin your email layout on different devices.
Expert tips
Consider using a combination of HTML text and images to provide a rich visual experience while maintaining deliverability.
Prioritize live text for key messaging, calls-to-action, and legal disclaimers.
If using image-based text for branding or aesthetic reasons, ensure the same content is available as live text elsewhere in the email.
Monitor your email deliverability rates closely, as a sudden drop might indicate an issue with content, including image usage.
Always host images on reliable, fast content delivery networks (CDNs) to ensure quick loading times.
Expert view
Expert from Email Geeks says they generally advise avoiding images in place of text because it can negatively impact user experience and accessibility, especially on mobile devices where images may not scale well.
2022-10-06 - Email Geeks
Expert view
Expert from Email Geeks notes that while older spam filters might have been concerned with image-to-text ratios, modern filters focus more on sender reputation and overall engagement, although image-only emails still pose accessibility issues.
2022-10-06 - Email Geeks
Summary and final thoughts
While the direct impact of using images instead of text on email deliverability is often overstated due to outdated spam filtering theories, it is still a factor to consider. The real concerns lie in user experience and accessibility, which indirectly affect deliverability through engagement metrics.
By adhering to best practices like optimizing images, providing robust alt text, and maintaining a healthy balance between images and live text, you can leverage the visual appeal of images without compromising your ability to reach the inbox. Ultimately, a good email experience leads to higher engagement, which in turn boosts your sender reputation and improves deliverability.
We provide tools to help you run a comprehensive email deliverability test to ensure your messages always reach their intended recipients.
Gmail. This hides important content, including unsubscribe links, and negatively impacts user engagement, which, in turn, can affect your deliverability over time. Poor engagement signals a lack of interest to inbox providers, potentially leading to future filtering issues.
We provide tools to help you run a comprehensive email deliverability test to ensure your messages always reach their intended recipients.
